2020 IDNR Impaired Waters List and Public Comment Opportunity


61% of rivers and streams are listed as impaired
Every two years, as required under the Clean Water Act, the Iowa Department of Natural Resources (IDNR) submits a list of impaired waterways in the state. These rivers, streams, lakes, reservoirs, and wetlands are listed as impaired if they do not meet the state’s water quality (WQ) standards for their intended use and need a water quality improvement plan. The reason(s) for an impairment can include a range of criteria like algae blooms, bacteria, turbidity, nutrients, pesticides, fish kills, and heavy metals like aluminum and mercury. 

The IDNR studied 1,300 water segments – 994 rivers and streams, 178 lakes and reservoirs, 128 wetlands – and 586 were considered impaired.
– Only 16% of the tested River and Stream segments met all WQ standards. 61% are impaired and 23% are potentially impaired
– 30% of the tested Lake and Reservoir segments met all WQ standards. 67% are impaired and 3% are potentially impaired
– 52% of the tested Wetland segments met all WQ standards. 23% are impaired and 26% are potentially impaired The main causes for the impairments of Iowa’s rivers and streams are indicator bacteria, biological, and fish kills. Indicator bacteria are types of bacteria used to detect and estimate the level of fecal contamination of water and biological means that insects, macroinvertebrates, and fish do not meet expected populations.

The IDNR is asking for public comments on this list of impaired waterbodies. Comments will be accepted through January 1, 2021. To send a comment you can email IRcomment@dnr.iowa.gov or write to:

Iowa Department of Natural Resources
Attention: IR Comments
Water Quality Monitoring & Assessment Section
Wallace State Office Building
502 East 9th Street
Des Moines, IA 50319

All Iowans deserve healthy waterbodies! We should be able to swim, fish, and kayak (or canoe) in our favorite river or stream. We must hold our representatives accountable and pass legislation to protect these resources. Join us as we advocate for our waterways.